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2022 Ozone Plan for the San Joaquin Valley

New Ozone Attainment Plan Now Under Development

The Clean Air Act (CAA) mandates the District to develop and submit a new attainment plan for the revised federal 8-hour ozone standard by August 2022 (2022 Ozone Plan) to the U.S. Environmental Protection Agency (EPA). In October 2015, EPA strengthened the standards for ground-level ozone from 75 parts per billion (ppb) to 70 ppb. The San Joaquin Valley air basin is classified as an “extreme” nonattainment area for this revised standard, with an attainment deadline of 2037.

To meet the 70 ppb standard, significant further reductions in ozone precursor emissions (NOx is primary precursor) will be needed. This will require concerted effort by the District, CARB, EPA, Valley residents, businesses, and other stakeholders to continue implementing effective and efficient air quality strategies. Given that over 85% of remaining NOx emissions in the Valley come from mobile sources under state and federal jurisdiction, it will be particularly important that continued efforts to reduce emissions from passenger vehicles, heavy duty trucks, locomotives, and other mobile sources be pursued.

The new ozone plan will build on existing air quality strategies, and the comprehensive NOx emissions reduction strategies included in existing ozone and PM2.5 attainment plans will greatly contribute to meeting the new federal ozone standard.

How is ground-level ozone formed?

Ozone is not emitted directly into the air, but is created by chemical reactions between oxides of nitrogen (NOx) and volatile organic compounds (VOC) in the presence of heat and sunlight. The Valley experiences its highest ozone levels in the summer season due peak solar radiation, periods of excessive heat, and meteorology that can trap emissions near the Valley floor. EPA’s current ozone standards are based on an 8-hour averaging period. More information is available on EPA’s website.

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What are the health effects of ozone exposure?

Exposure to high concentrations of ground level ozone can impact public health and cause a number of issues, including coughing, throat irritation, pain, and burning, discomfort in the chest, chest tightness or shortness of breath.

effects on health

Initial Implementation of New Ozone Standard Requirements

District staff have initiated development of the new 2022 Ozone Plan, and have taken action to address initial federal requirements, including approval of the 2020 Reasonably Available Control Technology (RACT) Demonstration for the 2015 8-Hour Ozone Standard and the Emissions Statement Program Certification in June 2020.

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Get Involved!

Public engagement is an important part of the planning process to involve the Community’s voices.

The District invites you to get involved in the public engagement process for ozone attainment planning efforts. To receive notices of upcoming public workshops and meetings, sign up for the District’s Ozone Plans Listserv.